One year after Colorado voters supported President Obama, single-party state government run by Democrats and legalized cannabis, they’re being asked to raise taxes by a billion dollars a year for schools. But you can throw that blue-state paradigm out the window for this one. The odds are likely with the no’s.

It’s not just that Coloradans have a long streak of rejecting statewide tax hikes, including measures designed specifically for schools. They defeated Gov. Roy Romer’s penny sales-tax plan in 1992 (Amendment 6) and crushed Sen. Rollie Heath’s Proposition 103 just two years ago. The climate just isn’t the same today as it was last year, and the election dynamics are very different.

More than 2.5 million Coloradans voted last year — three-quarters of a million more even than in 2010, when we had lively senate and govenor’s races.

The turnout in 2011? A little over 1 million.

“It’s going to be an old election,” pollster and political analyst Floyd Ciruli told me, referring to the average age of voters. Amendment 66 proponents “need deep liberals” to turn out, he added, including the young and minorities.

“If the election were held today, this would lose.”

The campaign director for Amendment 66 wouldn’t go that far when he spoke with me, but Andrew Freedman did say he wouldn’t relish the election today — confirming that a billion-dollar tax hike is one tough sell.

Not that he necessarily has a problem with ingrained skepticism. Voters shouldn’t be cavalier about any tax hike. But he’s optimistic, as all campaign directors should be, because he’s got lots of money to spend and several weeks left to persuade voters to come on board.

He points out that polling shows voters want to support more education funding — they do all the time at the local level, after all — but need to be convinced that new funds will end up in the classroom and be linked to academic achievement. So Colorado Commits to Kids will deploy its growing pile of cash — $5 million and counting — to making that case in the remaining month.

It helps, of course, that Freedman’s group so far has the paid advertising bullhorn to itself, and is likely to maintain a huge spending advantage even if opponents take to the airwaves.

If there’s a major X factor here, it’s the new election law and the fact that every voter now gets a ballot in the mail.

“This is a grand experiment,” Freedman said. “We don’t know what those voters who normally don’t vote in off-year elections will do once they get their ballots.”

Nor is that the only unknown. Will the floods affect public attitudes toward a tax hike? Do the successful recall elections against Democratic senators in El Paso and Pueblo counties suggest that conservatives are more highly motivated this fall? Recall opponents enjoyed a huge spending advantage, too, and yet failed to turn the tide.

To be sure, Amendment 66 supporters believe they have a far more attractive product than the losing senators. Even so, as Ciruli explains, “There is a presumption against a state tax hike and you have to overcome that presumption.”

And that means overcoming the ballot language itself, which poses the following stark question: “SHALL STATE TAXES BE INCREASED BY $950,100,000 ANNUALLY … .”

Still, Amendment 66 fans need hardly despair. It wasn’t so very long ago, after all, that a blue-tinged Colorado seemed inconceivable as well.